Tire carcass ply joining apparatus and method

ABSTRACT

A method forms a butt joint between ends of first and second plies and splices the first and second plies together. The method includes the steps of: positioning a first splice edge of a first ply at a first location; positioning a second splice edge of a second ply at a second location, the second splice edge being left bare; wrapping a gum strip around the first splice edge such that the first gum strip forms a U-shaped structure in section that allows the first gum strip to extend from a first planar side of the first ply over the first splice edge to a second opposite planar side of the first ply; not wrapping a gum strip around the second splice edge; placing the first splice edge in abutting relationship to the second splice edge; and stitching the first splice edge to the second splice edge such that stitches each extend from the first planar side of the first ply, through the gum strip, to the first planar side of the second ply.

FIELD OF THE INVENTION

The present invention relates generally to an apparatus and method forproducing a continuous preparation ply material for making pneumatictires and, more particularly, to an apparatus and method for making acontinuous carcass ply from multiple pieces.

BACKGROUND OF THE INVENTION

In the construction of a radial ply tire, a carcass consisting of one ormore preparation plies of elastomeric material is built up on agenerally cylindrical drum. The preparation ply is applied so thatreinforcing cords run from bead to bead in a direction that is generallyparallel to the axis of the drum. Thus, prior to making the carcass, thepreparation ply with the transversely extending reinforcing cords mustfirst be made.

It is known to manufacture the preparation ply by first producing asheet of elastomeric material in which reinforcing cords extendlongitudinally. During production, the sheet of elastomeric materialpasses between calendering rolls. The calendered sheet of material isthen cut into quadrilateral, for example, rectangular pieces,reoriented, and the calendered edges are then spliced together to form acontinuous strip of preparation ply material. The reorientation resultsin the reinforcing cords extending substantially parallel to the splicejoints and substantially perpendicular to the longitudinal direction ofthe preparation ply strip.

If the elastomeric material has metallic reinforcing cords, the lateralcalendered edges of the material have relatively straight and uniformedges. Thus, in the manufacture of a preparation ply that has metallicreinforcing cords, the adjacent ends of the strips are placed in directopposition and brought together without any overlap of the ends to forman end-to-end, or butt joint, splicing the two ends together. Thus, theends are held together only by the tackiness of the uncured rubber overthe area of the adjacent ends. Metallic reinforcing cords provide arelatively linear calendered edge that is suitable for a butt splicebond created by the tackiness of the elastomeric material.

However, if the elastomeric material has nonmetallic reinforcing cords,the lateral calendered edges of the material are not straight butundulating. Such curved calendered edges provide a non-uniform andvariable gap between the adjacent ends of the pieces and thus, aregenerally not considered suitable for a butt splice. Consequently,although a butt splice would be preferred in the manufacture of apreparation splice, an overlapping splice is often used to join the cutpieces having nonmetallic reinforcing cords. Therefore, there is a needfor improved apparatus and method for automatically making a preparationply with butt splices.

SUMMARY OF THE INVENTION

A first method in accordance with the present invention forms a buttjoint between ends of first and second plies and splices the first andsecond plies together. The first method includes the steps of:positioning a first splice edge of a first ply at a first location;positioning a second splice edge of a second ply at a second location;wrapping a gum strip around the first splice edge such that the gumstrip forms a U-shaped structure in section that allows the gum strip toextend from a first planar side of the first ply over the first spliceedge to a second opposite planar side of the first ply; not wrapping asecond gum strip around the second splice edge; placing the first spliceedge in abutting relationship to the second splice edge; stitching thefirst splice edge to the second splice edge such that stitches eachextend from the first planar side of the first ply, through the gumstrip, to a first planar side of the second ply; and curing the firstsplice edge to the second splice edge.

According to another aspect of the first method, the first and secondplies both have parallel wire cords spaced a predetermined distanceapart.

According to still another aspect of the first method, the gum strip hasa nominal thickness equal the predetermined distance of the first andsecond plies. Because gum strip thickness may vary plus or minus 35% to65%, the predetermined distance for the butt splice may varycorrespondingly plus or minus 70% to 130%.

According to yet another aspect of the first method, each stitch extendsfrom the gum strip to the second ply.

According to still another aspect of the first method, the gum strip isconstructed of a material at least 20% softer than a substrate materialof the first and second plies.

A second method forms a continuous material ply of the type used to makevehicle tires with the continuous material ply being made by joiningmultiple plies. The second method includes the steps of: positioning afirst splice edge of a first ply at a first location; positioning asecond splice edge of a second ply at a second location; wrapping a gumstrip around the first splice edge such that the gum strip forms aU-shaped structure in section that allows the gum strip to extend from afirst planar side of the first ply over the first splice edge to asecond opposite planar side of the first ply; not wrapping a gum striparound the second splice edge; placing the first splice edge in abuttingrelationship to the second splice edge at a third location; stitchingthe first splice edge to the second splice edge such that stitches eachextend from the first planar side of the first ply, through the gumstrip, to a first planar side of the second ply; and curing the firstsplice edge to the second splice edge.

According to another aspect of the second method, the second methodfurther includes the steps of: providing pairs of upper racks havingteeth and extending end-to-end having first upper racks movable withrespect to second upper racks; providing pairs of lower racks havingteeth and extending end-to-end adjacent the pairs of upper racks, thepairs of lower racks having first lower racks movable with respect tosecond lower racks; positioning the first edge of the first over teethof the first lower racks; positioning the second edge of the second plyover teeth of the second lower racks; and clamping the first and secondplies between the pairs of upper racks and the pairs of lower racks;simultaneously engaging teeth of all first upper racks with teeth of allsecond upper racks; and teeth of all first lower racks with teeth of allsecond lower racks to firmly press the first edge of the first plyagainst the second edge of the second ply to splice the first and secondplies together.

According to still another aspect of the second method, the gum strip isconstructed of a material at least 20% softer than a substrate materialof the first and second plies.

A system in accordance with the present invention forms a continuousmaterial ply of the type used to make vehicle tires with the continuousmaterial ply being made by joining multiple plies. The system includes:positioning a first splice edge of a first ply at a first location;positioning a second splice edge of a second ply at a second location;wrapping a gum strip around the first splice edge such that the gumstrip forms a U-shaped structure in section that allows the gum strip toextend from a first planar side of the first ply over the first spliceedge to a second opposite planar side of the first ply; not wrapping agum strip around the second splice edge; placing the first splice edgein abutting relationship to the second splice edge at a third location;stitching the first splice edge to the second splice edge such thatstitches each extend from the first planar side of the first ply,through the gum strip, to a first planar side of the second ply; andcuring the first splice edge to the second splice edge.

According to another aspect of the system, an apparatus applies a gumstrip at a butt joint thereby splicing the first edge to the secondedge. The apparatus may include a conveyor for providing gum stripshaving a desired length and thickness; and a transfer device forautomatically removing the gum strips from the conveyor and placing thegum strip at the butt joint.

According to still another aspect of the system, the transfer devicecomprises a vacuum head.

According to yet another aspect of the system, the vacuum head isresiliently mounted to the transfer device to provide a force againstthe gum strip upon the gum strip being placed at the butt joint.

According to still another aspect of the system, a cutting apparatusautomatically cuts the gum strip to the desired length.

According to yet another aspect of the system, a controller isoperatively connected to the conveyor and the transfer device to operatethe conveyor and the transfer device.

According to still another aspect of the system, the gum strip isconstructed of a material at least 20% softer than a substrate materialof the first and second plies.

An apparatus for use with the present invention is provided thatautomatically butt splices a preparation ply having metallic ornonmetallic reinforcing cords. The apparatus is relatively simple indesign and less expensive than other machinery used to butt splice apreparation ply. The apparatus provides a high quality butt spliceregardless of the reinforcing cord material and therefore, is especiallyuseful in making a preparation ply having nonmetallic reinforcing cords.

More specifically, the apparatus forms a butt joint between ends offirst and second plies to splice the plies together. The apparatus haspairs of upper racks that extend end-to-end and each pair of upper rackshas first and second upper racks that are movable with respect to eachother. In addition, pairs of lower racks extend end-to-end adjacent thepairs of upper racks, and each pair of lower racks has first and secondlower racks that are movable with respect to each other. The first andsecond lower racks support ends of first and second plies, respectively.A clamp drive is connected to the pairs of upper racks and is operableto move the upper racks toward the lower racks to clamp the ends of thefirst and second plies between the upper and lower racks. An engagementdrive is connected to the upper and lower racks and is operable tosimultaneously move all of the first and second racks with respect toeach other to firmly press the ends of the first and second pliestogether, thereby forming a butt joint splicing the ends of the firstand second plies together.

The apparatus automatically applies a gum strip to a butt joint joiningtwo preparation plies together. The apparatus is fast, reliable andautomatically operable with the butt splicer described herein andtherefore, is especially useful in making a preparation ply havingnonmetallic reinforcing cords.

More specifically, the apparatus has a conveyor for providing a gumstrip of a desired length. A transfer device then automatically removesthe gum strip from the conveyor and places the gum strip on the buttjoint.

A third method for use with the present invention positions an end of afirst material ply section over teeth of the first lower racks andpositioning an end of a second material ply section over teeth of thesecond lower racks. Next, the first and second material ply sections areclamped between the pairs of upper racks and the pairs of lower racks.Then, the teeth of all the first upper and lower racks aresimultaneously engaged with the teeth of all the second upper and lowerracks to firmly press the ends of the first and second material pliestogether to form a butt joint that splices the first and second materialplies together. The third method applies a gum strip only over a buttjoint splicing end of first preparation ply by providing a gum striphaving a desired length and then, automatically placing the gum strip onthe butt joint.

These and other objects and advantages of the present invention willbecome more readily apparent during the following detailed descriptiontaken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described by way of example and withreference to the accompanying drawings, in which:

FIG. 1 schematically shows two ply segments placed adjacent each other.

FIG. 2 schematically shows one edge of one of the ply segments preparedfor joining.

FIG. 3 schematically shows a butt splice in accordance with the presentinvention.

FIG. 4 is a schematic illustration of a cord preparation plymanufacturing line having a butt splicer and gum strip applier for usewith the present invention.

FIG. 5 is a side view of the butt splicer and the gum strip applier ofFIG. 4 .

FIG. 6 is a side view of the butt splicer of FIG. 5 .

FIG. 7 is a partial perspective view of a portion of the butt splicer ofFIG. 5 that illustrates the plurality of pairs of upper and lower racks.

FIG. 8 is an end view of the butt splicer of FIG. 5 .

FIG. 9 is a schematic block diagram of part of a control system used tocontrol the operation of the butt splicer and gum strip applier of FIG.4 .

FIG. 10 is a schematic block diagram of another part of a control systemused to control the operation of the butt splicer and gum strip applierof FIG. 4 .

FIG. 11 is a flowchart of a subroutine implemented by the control systemof FIG. 9 for positioning a preparation ply piece prior to a buttsplicing cycle.

FIG. 12 is an end view illustrating a first condition of a rack on thebutt splicer of FIG. 4 in executing the butt splicing cycle of FIG. 9 .

FIG. 13 is an end view illustrating a second condition of a rack on thebutt splicer of FIG. 4 in executing the butt splicing cycle of FIG. 9 .

FIG. 14 is an end view illustrating a third condition of a rack on thebutt splicer of FIG. 4 in executing the butt splicing cycle of FIG. 9 .

FIG. 15 is an end view illustrating a fourth condition of a rack on thebutt splicer of FIG. 4 in executing the butt splicing cycle of FIG. 9 .

FIG. 16 is a flowchart of a subroutine implemented by the control systemof FIG. 9 for butt splicing the preparation ply materials.

FIG. 17 illustrates how the upper pairs of racks are non-rigidly mountedin jaw mounting brackets on the butt splicer of FIG. 5 .

FIG. 18 is an end view of the gum applier of FIG. 5 .

FIG. 19 is a side view of the gum applier of FIG. 5 .

FIG. 20 is a partial top view of the gum applier of FIG. 5 illustratinghorizontal drive components.

FIG. 21 is a partial end view of the gum applier of FIG. 5 illustratingvertical drive components.

FIG. 22 is a flowchart of a subroutine implemented by the control systemof FIG. 9 for cutting a gum strip to length.

FIG. 23 is a flowchart of a subroutine implemented by the control systemof FIG. 9 for picking up a gum strip with a vacuum head.

FIG. 24 is a flowchart of another subroutine implemented by the controlsystem of FIG. 9 for applying a gum strip with a vacuum head.

FIG. 25 is a state diagram illustrating the operation of the controlsystem of FIG. 9 for simultaneously operating the butt splicer and gumstrip applier of FIG. 5 .

DETAILED DESCRIPTION OF EXAMPLES OF THE PRESENT INVENTION

Referring to FIG. 4 , in a preparation ply manufacturing line 20, astrip of calendered material 22 may be fed from calender rolls (notshown) in a known manner. The calendered material 22 may be 0.040 inchto 0.060 inch thick and have cords 24 made from a metallic ornonmetallic material extending longitudinally generally parallel to thecalendered edges 26. Non-metallic cords 24 may be less rigid thanmetallic cords resulting in the calendered edges 26 being nonlinear andundulating. The calendered material may be fed by a conveyor 28 past acutter 30, which cuts the calendered material 22 to desired lengths,depending on the application. The resulting rectangular pieces 32 maythen be transferred onto a transverse infeed conveyor 34. The pieces maythen be conveyed in a downstream direction 35 to a butt splicing machine36 that forms butt joints 40 between the calendered edges 26 of the cutpieces 32 to form a continuous preparation ply strip 38. The butt joints40 may be reinforced by respective gum strips 42 that are placed overthe joints 40 by a gum strip applier 44. The resulting continuouspreparation ply strip may be collected on windup rolls 43 in a knownmanner. The continuous preparation ply strip 38 may have nonmetalliccords 24 that are substantially parallel to the butt joints 40 and gumstrips 42 and are transverse to a longitudinal axis 46 of thepreparation ply strip 38.

For purposes of this description, the term “downstream” is used toidentify the direction of motion of the preparation ply material 38through the butt splicer 36 and gum strip applier 44 (e.g., from rightto left as viewed in FIG. 4 ). The term “upstream” is used to designatea motion in an opposite direction. Components of the butt splicer 36that are identified as “downstream” are located closer to the gum stripapplier 44 than components identified as being “upstream”.

FIG. 5 is a side view of a portion of the preparation ply manufacturingline 20 and a strip of calendered material 22 that includes the infeedconveyor 34, the butt splicer 36, and the gum strip applier 44.Preparation equipment 48 for the gum strip applier 44 may feed the gumstrip from a roll and separate and wind up a covering over the gum stripadhesive.

Referring to FIGS. 7 and 8 , the butt splicing machine 36, or buttsplicer, may have a frame 72 that supports floating tables 70 on boththe upstream and downstream sides of the butt splicing machine. Pairs ofupper racks 50 and pairs of lower racks 52 may be mounted to extendtransversely across the width of the butt splicing machine 36. Each pairof upper racks 50 may comprise a nonpivotable upstream rack 54 havingteeth 56 engageable with teeth 58 of a pivotable downstream rack 60.Similarly, each pair of lower racks 52 may comprise a nonpivotableupstream rack 62 having teeth 64 engageable with teeth 66 of a pivotabledownstream rack 68. The pairs of lower racks 52 may be fixed inelevation immediately adjacent the table 70 that supports the cut strips32 being fed by the infeed conveyor 34 to the butt splicer 36.

Each of the upper upstream racks 54 may be mounted to a lower end of arespective upper nonpivotable upstream jaw mounting bracket 75 mountedon a slide 76. The slide 76 may be slidably mounted on a linear guide 77fixed to an upper pair of cross rails 78 of the frame 72. Each of theupper downstream racks 60 may be mounted to a lower end of a respectiveupper pivotable downstream jaw mounting bracket 79. Upper ends of eachof the upper jaw mounting brackets 75, 79 may be mechanically connectedto a clamp drive comprised of a respective upper clamping actuator 82(e.g., a pneumatic cylinder as shown in FIG. 8 ). The cylinders 82 maybe re mounted to a truss 95 mounted on gearboxes 97 on the frame 72.

The gearboxes 97 may be connected by a shaft 99 and operated by ahandwheel 101. Thus, turning the handwheel 101 may adjust the verticalposition of the cylinders 82 and the upper pairs of racks 50. The upperends of each of the jaw mounting brackets 75, 79 may be pivotallyconnected via a pivot pin 80 to a distal end of a cylinder rod 81 of arespective cylinder 82. Simultaneous operation of the cylinders 82 maysimultaneously move the upper jaw mounting brackets 75, 79 andrespective pairs of upper racks 50 downward toward the pairs of lowerracks 52. Reversing the operation of the cylinders 82 may move the upperracks 50 away from the lower racks 52.

As shown in FIG. 7 , the upper downstream racks 60 may be pivotable withrespect to respective upper upstream racks 54 by means of an engagementdrive comprised of respective upper engagement actuators 83 (e.g., apneumatic cylinder). Specifically, the cylinders 83 may be mounted onrespective upper downstream jaw mounting brackets 79; and, as shown inFIG. 6 , distal ends of respective cylinder rods 85 may be connected torespective opposed upper upstream jaw mounting brackets 75. Simultaneousoperation of the engagement actuators 83 may cause the upper downstreamjaw mounting brackets 79 and respective upper downstream racks 60 topivot toward the upper upstream jaw mounting brackets 75 and therespective upper upstream racks 54, thereby engaging their respectiveteeth 58, 56. Reversing the operation of the engagement cylinders 83 maycause the upper downstream racks 60 to move simultaneously away from theupper rear racks 54, thereby disengaging their respective teeth 58, 56.

Each of the lower upstream racks 62 may be mounted to a lower end of arespective lower upstream nonpivotable jaw mounting bracket 84 attachedto a lower pair of cross rails 87 fixed to the frame 72. Each of thelower downstream racks 68 may be mounted to a lower end of a respectivelower pivotable downstream jaw mounting bracket 88. Upper ends of eachof the lower jaw mounting brackets 84, 88 may be pivotally connected viaa pivot pin 89. The lower downstream racks 68 may be pivotable withrespect to respective lower upstream racks 62 by means of an engagementdrive comprised of respective lower engagement actuators 90 (e.g.,pneumatic cylinders). Specifically, the actuators 90 may be mounted onrespective lower downstream jaw mounting brackets 88; and, as shown inFIG. 6 , distal ends of respective cylinder rods 91 may be connected torespective lower upstream jaw mounting brackets 84. Simultaneousoperation of the engagement actuators 90 may cause the lower downstreamjaw mounting brackets 88 and respective lower downstream racks 68 topivot toward the lower upstream jaw mounting brackets 84 and therespective lower upstream racks 62, thereby engaging their respectiveteeth 66, 64. Reversing the operation of the engagement actuators 90 maycause the lower downstream racks 68 to move simultaneously away from thelower upstream racks 62, thereby disengaging their respective teeth 66,64.

Referring to FIG. 9 , the operation of the floating table 70 andcylinders 90, 82, 83 may be controlled by the operation of solenoids 94transferring pressurized air from a source 96. The operational states ofthe solenoids may be commanded by output signals from a controller 98(e.g., a programmable logic controller, microcontroller, etc.). Theoperation of the controller 98 may be controlled by input devices (e.g.,a user 1/0 1 00, an edge sensor 102, etc.) The controller 98 may alsoprovide output signals that command the operation of an infeed conveyormotor 104 (FIG. 2 ) and an outfeed conveyor motor 106 that operate therespective infeed and outfeed conveyors 34, 108.

The operation of the butt splicer 36 may be controlled by various cyclesof operation programmed into the controller 98 as a group ofsubroutines. For example, a first subroutine (FIG. 7 ) may position cutpieces 32 in the butt splicer 36 in preparation for making the buttjoint. The process of FIG. 5 may start with a preparation ply 38 in thebutt splicer 36 and a completed butt joint.

Referring to FIGS. 4, 5, 9, and 11 , to position the preparation ply 38and a new cut piece 32 for the next splice, the controller 98 mayprovide, at 502, output signals to run the infeed and outfeed conveyormotors 104, 106, respectively. Simultaneously, the controller 98 mayprovide an output signal to the solenoid 94 for adjusting state andtransferring pressurized air to the floating tables 70. Thus, materialmay be moved over the butt splicer 36 with minimal friction from asubjacent support. Simultaneous operation of the infeed and outfeedconveyors 34, 108 may move the preparation ply strip 38 in a downstreamdirection 35, as viewed in FIGS. 4, 5, and 12 . The motion of thepreparation ply strip 38 may result in a trailing edge 110 (FIG. 12 )passing beneath an edge sensor 102 mounted on the butt splicer 36. Upondetecting the trailing edge 110, the edge sensor 102 may provide anoutput signal, at 504, to the controller 98.

The controller 98 may monitor the operation of the outfeed conveyor 108to determine when the trailing edge 110 has been moved to a desiredposition with respect to the teeth 66 of the lower downstream rack 68.The distance between the point at which the trailing edge 110 is sensedby the edge sensor 102 and the final position of the trailing edge 110on the lower downstream rack 68 may be a known value. Therefore, theoperation of the outfeed conveyor motor 106 may be precisely controlledsuch that the outfeed conveyor 108 stops when the trailing edge 110 isat its desired location on the lower downstream rack 68. The desiredlocation of the trailing edge 110 may vary depending on the design ofthe butt splicer 36, the depth of the teeth of the racks, the nature ofthe preparation ply material 38, etc.

The desired position of the trailing edge 110 may be set back from thefront edges of the teeth 66 of the lower downstream rack 68. However,the amount of setback of the trailing edge 110 may be determinedexperimentally in each application and may, for example, be a distanceequal to somewhat less than half the length of the teeth 66. Detectingwhen the trailing edge 110 is in position may be accomplished in severalways. In one, the outfeed conveyor motor 106 may have an encoder 112attached thereto with each output pulse from the encoder representing anincremental displacement of the outfeed conveyor 108. Thus, thecontroller 98 may detect and count output pulses from the encoder 112and detect, at 506, when the trailing edge 110 is at its desiredposition on the teeth 66 of the lower downstream rack 68. In another, ifthe speed of the outfeed conveyor 108 is fixed, the controller 98 maystart an internal timer that counts milliseconds required to move thetrailing edge 110 from its position under the edge sensor 102 to adesired position on the teeth 66 of the lower downstream rack 68. Whenthe controller 98 determines, at 506, that the trailing edge 110 is atits desired position, the controller may provide, at 508, an “STOP”output signal to the outfeed conveyor motor 106. In addition, thecontroller 98 may provide an output signal switching the state ofsolenoid 94 to remove the supply of pressurized air from the downstreamfloating table 70 thereby providing a more rigid support for the cutpiece 38.

Simultaneously with moving of the preparation ply 38, the operation ofthe infeed conveyor 34 by the controller 98 may also cause a new cutpiece 32 to move in the downstream direction 35 toward the butt splicer36. After detecting the trailing edge 110 of the preparation ply 38, theedge sensor 102 may detect the leading edge 114 of the next cut piece 32to be spliced to the preparation ply strip 38 with its output changingstate, at 510. Upon detecting a change of state, the controller 98 maybegin counting pulses from an encoder 116 connected to the infeedconveyor motor 104. By counting encoder pulses, the controller 98 maydetermine when the leading edge 114 is at a desired position on theteeth 64 of the lower upstream rack 62. Again, the desired position ofthe leading edge 114 may vary depending on design of the butt splicer36, the depth of the teeth of the racks, the nature of the preparationply material, etc. The desired position of the leading edge 114 may bedetermined in the same way as described above with respect to thedesired position of the trailing edge 110.

Upon detecting, at 512, the desired position of the leading edge 114,the controller 98 may provide, at 514, an “STOP” output signal to theinfeed conveyor motor 104. The infeed conveyor 34 and the outfeedconveyor 108 may normally have about equal speeds or the outfeedconveyor may run slightly faster than the infeed conveyor to increasethe gap between the trailing edge 110 of the preparation ply 38 and theleading edge 114 of the ply section 32.

The controller 98 may also provide an output signal switching the stateof solenoid 94 for removing the supply of pressurized air from theupstream floating table 70 and for providing a more rigid support forthe cut piece 32. At this point, the edges 110, 114 may be located atdesired locations on respective teeth 66, 64 of the lower rear andforward racks 68, 62.

After the edges 110, 114 are at the desired locations, the butt splicer36 may form a butt splice joining the preparation ply strip 38 with thenew cut piece 32. Referring to FIG. 16 , a process for making a buttsplice may begin with the controller 98 providing, at 516, an outputsignal to the solenoid 94 causing the solenoid to switch states and portpressurized air to the clamp cylinders 82. The clamp cylinders 82 maysimultaneously lower the plurality of upper racks 50 until the upperdownstream racks 60 contact a portion of the preparation ply strip 39adjacent the trailing edge 110 being supported by respective lowerdownstream racks 68.

Simultaneously, the upper upstream racks 54 may contact a portion of thecut strip 32 adjacent the leading edge 114 supported by the lowerupstream racks 62, as shown in FIG. 13 . The time required to move theupper racks 54 to their clamped position may be measured and thecontroller 98 may initiate an internal timer equal to that clampingoperation time. Therefore, when that time expires, the controller 98 maythen determine, at 518, the upper pairs of racks 50 have been moved totheir respective clamped positions.

Thereafter, the controller 98 may then provide, at 520, output signalsto the solenoids 94 b, 94 c changing the states of those solenoids andporting pressurized air into the upper and lower engagement cylinders83, 90, respectively. The engagement cylinders 83, 90 may move the upperand lower downstream racks 60, 68 toward their corresponding matingupper and lower upstream racks 54, 62. The clamped upper and lowerdownstream racks 60, 68 may move the preparation ply 38 in an upstreamdirection 117 (FIG. 13 ) to bring the preparation ply strip trailingedge 110 into contact with the cut piece leading edge 114 in an abuttingrelationship. Continued motion of the upper and lower downstream racks60, 68 may firmly force the preparation ply strip trailing edge 110against the cut piece leading edge 114 to form the butt splice 40 (FIG.14 ). The tackiness of the elastomeric material may maintain the cutpiece leading edge 114 in contact with the preparation ply striptrailing edge 110. That motion may continue until the teeth 58, 66 ofthe respective upper and lower downstream racks 60, 68 are fully engagedwith the teeth 56, 64 of the respective upper and lower upstream racks54, 62, as shown in FIG. 14 .

As previously described, the controller 98 may determine, at 522, theupper and lower downstream racks 60, 68 are fully engaged withrespective upper and lower upstream racks 54, 62. The controller 98 maythen provide, at 524, an output signal to switch the state of solenoid94 a thereby reversing the porting of pressurized air to the clampcylinders 82. The actuation of the clamp cylinders 82 may cause thepairs of upper racks 50 raise and move back to an undamped position, asshown in FIG. 15 . Immediately thereafter, the controller 98 mayprovide, at 526, output signals to the solenoids 94 b, 94 c to switchthe states of the upper and lower engagement cylinders 83, 90 therebymoving the upper and lower downstream racks 60, 68 in the downstreamdirection 35 away from the upper and lower upstream racks 54, 62. Thisoperation may cause the racks to open to the position illustrated inFIG. 12 .

As the upper and lower downstream racks 60, 68 move toward therespective upstream racks 54, 62, the downstream racks 60, 68 and thepreparation ply 38 may move simultaneously. However, after thepreparation ply trailing edge 110 contacts the cut piece leading edge114, the upper and lower downstream racks 60, 68 may have a relativemotion with respect to the preparation ply strip 38 and therefore mustslide over the major surfaces of the preparation ply strip 38 withoutcausing damage. The sides 93 of the pivoting downstream racks 60, 68 maybe coated with a polytetrafluoride (PTFE) material. In addition, theteeth of the upper and lower downstream racks 60, 68 may be beveled attheir leading edges of contact, that is, the surface 92 (FIG. 7 ). Theconfiguration of the beveled surface 92 may be application dependent andvary with the nature of the ply material, the length of the racks, etc.The beveled surface 92 may have an angle of about 10° with respect tothe side surface 93 of the rack or an angle of about 20°. An angleproviding optimum performance may be determined experimentally.Similarly, the desired length of the beveled surface 92 and the desireddepth from the side surface 93 may also be determined experimentally.Such a beveled surface 92 may facilitate sliding motion of thedownstream racks 60, 68 over the preparation ply strip 38 withoutgouging or otherwise causing damage.

The butt splicer 36 may have a plurality of pairs of upper and lowerracks 50, 52 for a more consistent, higher quality butt splice than ifthe upper and lower racks 50, 52 extend continuously across a full widthof the butt splicer 36. Reliability and quality of the butt splice maybe further improved by nonrigidly mounting the upper racks 54, 60 torespective upper jaw mounting brackets 75, 79. The nonrigid mounting ofthe racks 54, 60 may be identical; and the mounting of rack 54 onto ajaw mounting bracket 75 is shown in FIG. 17 . Shoulder bolts 122 mayextend through slots 123 in the jaw mounting bracket 75 and threadedlyengage the rack 54. Thus, the rack 54 may be nonrigidly mounted to therespective jaw mounting bracket 75, but also be free to move relativethereto by an amount depending on the size of the slots 123. Further,the end of the jaw mounting bracket 75 may have a generally L-shapednotch 124 extending across a width of the jaw mounting bracket 75. Theslots 123 may intersect a first notch surface 125 that contacts a rearsurface of the rack 54. A perpendicular surface 126 of the notch 124 maybe curved (e.g., a 30 inch radius) to allow the rack 54 to rock thereon.Such nonrigid mounting of the upper racks 54, 60 to respective jawmounting brackets 75, 79 may substantially improve the quality of thebutt splice 40.

The operation of the butt splicer 36 may provide reliable and highquality butt joints in the formation of a preparation ply strip.Further, the butt splicer 36 may form butt splices that aresubstantially perpendicular to the infeed conveyor 34, as well as buttsplices that are oblique with, or angled slightly from, a lineperpendicular to the infeed conveyor. Referring to FIG. 6 , a forwardleg 131 of the frame 72 of the butt splicer 36 may be pivotally mountedto a base plate 132. A rearward leg (not shown) of the frame 72 may besupported by a caster 133 that rides on the base plate 132. A ball screwand nut assembly 134 may connect the rearward leg and a handwheel 135.Turning the handwheel 135 may rotate the ball screw and cause the nut,pivotally attached to the rearward leg of the frame 72, to travel alongthe ball screw. As the nut moves, the rearward leg of the frame 72 maypivot with respect to the forward leg 131 thereby skewing the rows ofupper and lower racks 50, 52 with respect to a line perpendicular to alongitudinal centerline of the infeed conveyor 34. An indicatorassociated with the handwheel 135 may be calibrated in one degreeincrements. Permitting the frame 72 to pivot through an angle of up toabout 10 degrees may be sufficient for most applications.

The butt joint may be stronger and more stable during the tiremanufacturing process if it is covered with a gum strip laidperpendicularly across the butt joint. For an efficient operation, thegum strip applier 44 may operate simultaneously with the butt splicer36. Therefore, the gum strip applier 44 may be positioned, with respectto the butt splicer 36, such that, simultaneously with the preparationply trailing edge being positioned at the butt splicer 36, the mostrecently formed butt splice may be positioned at a location suitable fora gum strip to be applied by the gum strip applier 44.

Referring to FIG. 18 , the outfeed conveyor 108 may be supported by abase 126. The gum strip applier 44 may have a frame 127 independentlysupported by a base 128 and legs 129. Thus, the outfeed conveyor 108 andgum strip applier 44 may be positioned independently with respect to thebutt splicer 36. The gum strip applier 44 may be positioned such thatwhen a butt splice is formed on the butt splicer 36, a previously madebutt splice may be located on the outfeed conveyor 108 at a location 140permitting the gum strip applier 44 to apply a gum strip to thepreviously made butt splice. Referring to FIG. 19 , the gum stripapplier 44 may have a gum strip conveyor 142 and a vacuum head assembly144. The vacuum head assembly 144 may have two degrees of freedompermitting removal of a gum strip from the strip conveyor 142 andplacement a butt splice positioned at the upstream location 140.

Referring to FIG. 20 , an X-axis horizontal drive motor 146 may bemechanically connected to one end of a ball screw 148; and a sprocket150 may be mounted on an opposite end of the ball screw 148 foroperatively engaging a timing belt 152. The timing belt 152 may befurther connected to a second sprocket 154 mounted on an end of a secondball screw 156. The ball screws 148, 156 may have respective ball nuts158, 160 that support and carry a carriage 162 supported and guided inlinear motion by linear bearings 163. As shown in FIG. 20 , the carriage162 may support the vacuum head assembly 144. The vacuum head assembly144 may have a length substantially equal to the length of the buttsplice (e.g., the full width of the preparation ply strip). Rotation ofthe horizontal drive motor 146 may simultaneously move the ball nuts158, 160 (FIG. 20 ), the carriage 162, and the vacuum head assembly 144in a horizontal direction substantially parallel to a longitudinal axisof the preparation ply strip.

Referring to FIG. 21 , a Z-axis vertical drive motor 164 may be mountedon, and supported by, the carriage 162 and may be mechanically connectedto one end of a first ball screw 166. A first timing sprocket 168 may bemounted on an opposite end of the first ball screw 166 and operativelyengage a timing belt 170 that also engages a sprocket 172 mounted on anend of a second ball screw 174. First and second ball nuts 176, 178 maybe rotatably mounted on the respective ball screws 166, 178 andconnected to a vacuum head plenum 180, which is guided in linear motionby linear bearings 181.

Referring to FIG. 19 , a vacuum head 182 may be supported by verticalposts 184 fixed to the plenum 180. Biasing components, such ascompression springs 181, may be mounted on the posts 184 between thevacuum head 182 and the plenum 180. The vacuum head 182 may have alength extending across substantially the entire width of the outfeedconveyor 108, as well as the length of a butt splice in the preparationply strip. Thus, operation of the vertical drive motor 164 may raise thevacuum plenum 180 and the vacuum head 182 below the outfeed conveyor108.

Referring to FIG. 10 , the controller 98 may provide output signals tothe strip conveyor motor 186 and receive input pulses from a stripconveyor encoder 188 by which the controller 98 may determine the linearmotion of the strip conveyor 142. Similarly, in response to outputsignals commanding the horizontal and vertical drive motors 146, 164,the controller 98 may receive feedback signals from the encoders 190,192 representing motion of the vacuum head 182. The controller 98 mayalso operatively connect to a vacuum pump 194 that applies partialvacuum pressure to the plenum 180. A vacuum may be applied and releasedby the vacuum head 182 by means of a vacuum release valve 196 connectingthe vacuum head plenum 180 and the vacuum head 182. When in its firststate, the valve 196 may close the vacuum head 182 to atmosphere andopen it to the 180 thereby applying a partial vacuum to the vacuum head182. In its opposite second state, the valve 196 may close theconnection between the vacuum head 182 and the plenum 180 and open thevacuum head to atmosphere thereby dissipating the partial vacuumtherein. The controller 98 may also connect to a solenoid 94 e forchanging the state of a knife cylinder 198 thereby operating a knife 200on the gum strip preparation equipment 48 (FIG. 5 ) to cut the gumstrips to desired lengths.

There may be three independent, but coordinated, operations orsubroutines executed by the gum strip applier 44. Referring to FIG. 19 ,first a gum strip 42 may be moved by the conveyor 142 to a locationready for transfer to the vacuum head 182. A second operation allows thevacuum head 182 to pick up the gum strip from the conveyor 142 and beready to apply the gum strip to the butt joint. A third operation mayapply the gum strip to the butt joint after the butt joint has beenmoved to the desired location 140 (FIG. 18 ). Referring to FIGS. 10, 19,and 22 , to cut a gum strip to length, the controller 98 may provide, at552, an output signal to operate the strip conveyor motor 186 therebycausing the strip conveyor 142 to feed the gum strip.

As the gum strip 42 feeds, the controller 98 may monitor and countoutput pulses from the strip conveyor encoder 188. When the controller98 counts, at 554, a number of pulses equal to the desired length of thegum strip, the controller may provide, at 556, a “STOP” output signal tothe strip conveyor motor 186. Thereafter, the controller 98 may provide,at 558, an output signal commanding the solenoid 94 e to change statethereby porting pressurized air to the knife cylinder 198 and operatingthe knife 200. Immediately thereafter, an output signal from thecontroller 98 may change state thereby reversing the state of solenoid94 e and returning the knife cylinder 198 to its initial position.Operation of the knife cylinder 198 may reciprocate the knife 200 andestablish a cut end for the gum strip 145. This action may provide a gumstrip on the strip conveyor 142 that is of the desired length (e.g., thelength of the butt strip 40).

Thereafter, the controller 98 may provide, at 560, a “START” outputsignal to the strip conveyor motor 186; and the strip conveyor 142 maytransport the gum strip 42 across the width of the outfeed conveyor 108.Again, the controller 98 may monitor and count output pulses from thestrip conveyor encoder 188 and determine when the cut gum strip is inits desired position. When that position is detected, at 562, thecontroller 98 may provide, at 564, a “STOP” output signal to the stripconveyor motor 186. At this point, a gum strip 42 of desired length maybe located on the strip conveyor 142 at a location ready to be picked upby the vacuum head 182.

Referring to FIGS. 10, 18, and 23 , to pick up the gum strip from thegum strip conveyor 142, the vacuum head 182 may elevated and thecarriage 162 may be positioned to locate the vacuum head 182 at adownstream location above the gum strip conveyor 142 ready to pick up agum strip. The controller 98 may provide, at 565, an output signal tothe vacuum release valve 196 closing the vacuum head 182 to atmosphereand opening the vacuum head to the plenum 180. A vacuum may then beapplied to the vacuum head 182. The controller 98 may also provide, at565, output signals to the Z-axis vertical drive motor 164 therebyrotating the ball screws 166, 174 in a direction to move the vacuum head182 vertically downward toward the gum strip conveyor 142. Thecontroller 98 may monitor and count output pulses from the verticaldrive encoder 192 and detect, at 566, when the vacuum head 182 is at itsdesired position immediately above the strip conveyor 142. At thatposition, the vacuum head 182 may be sufficiently close to the stripconveyor 142 such that the vacuum head 182 may lift the gum strip offthe gum strip conveyor 142.

The controller 98 may then provide, at 567, output signals to the Z-axisvertical drive motor 164 and the X-axis horizontal drive motor 146causing the vacuum head 182 to move to a ready position immediatelyabove the location 140 at which the butt joint is located. Thecontroller 98 may be programmed to first operate the vertical drivemotor 164 to raise the vacuum head 182 and thereafter operate thehorizontal drive motor 146 to move the vacuum head horizontally to aready position over the butt joint location 140. Alternatively, in otherapplications, the motors 146, 164 may operate simultaneously to move thevacuum head 182 to a ready position.

The controller 98 may monitor output pulses from the encoders 190, 192in the manner previously described to detect, at 568, which the vacuumhead 182 is at the ready position. Thereafter, the controller 98 mayprovide, at 569, output signals to either or both the motors 146, 164commanding them to stop the vacuum head 182 at the ready position.

Referring to FIGS. 10, 18, 19, and 24 , to apply the gum strip to thebutt joint, a butt joint may be moved to the location 140 beneath thevacuum head 182 at the ready position. The controller 98 may provide, at572, output signals to the Z-axis vertical drive motor 166 rotating ballscrews 166, 174 in a direction causing the vacuum head 182 to loweronto, and contact the preparation ply strip 38. The gum strip may have alength extending over substantially the entire length of the buttsplice. Further, the gum strip may have a width extending across thebutt splice 40 and over a portion of the major surfaces on both sides ofthe butt splice. The vacuum head 182 may be resiliently and movablymounted to the vacuum head plenum 180. Therefore, as the vertical drivemotor 164 continues to move the plenum 182 downward, the vacuum head 182may contact the preparation ply strip 38 and the springs 181 may apply adownward biasing force against the vacuum head 182 thereby applying adesired application force against the gum strip 42. That force may bedetermined by spring constants of the springs 181 and may be effectiveto cause adhesive on the gum strip 42 to better adhere to thepreparation ply strip 38.

Again, the controller 98 may monitor the output pulses from the encoder190 and detect, at 573, when the vacuum head 182 has been moved to itslowermost position. Thereafter, the controller 98 may provide, at 574, a“STOP” output signal to the vertical drive motor 164. In addition, thecontroller 98 may provide an output signal to the vacuum release valve196 changing the state of the valve such that the fluid connectionbetween the vacuum head plenum 180 and the vacuum head 182 is blockedand the vacuum head 182 is open to atmosphere. At this point, thecontroller 98 may allow the vacuum head 182 to remain at its lowermostposition and allow the adhesive on the gum strip to set. Such a time maybe determined by an internal timer in the controller 98 and may be setfrom zero to any desired number of seconds.

Thereafter, the controller 98 may provide, at 575, output signalscommanding the drive motors 146, 162 to move the vacuum head 182 back tothe pickup position above the gum strip conveyor 142. As describedabove, the controller 98 may monitor the encoders 190, 192 to detect, at576, when the vacuum head 182 is at the pickup position; and thereafter,at 577, the controller may provide “STOP” output signals to the drivemotors 146, 164.

As described above, it may be desirable that the gum strip applier 44operate simultaneously with the butt splicer 36 to apply the gum strip42 over the most recently formed butt splice 40 while the butt spliceris splicing the next cut piece 32 to the preparation ply strip 38.Therefore, prior to a butt splice 40 being moved to the position 140,the gum strip applier 44 may prepare a gum strip 42 for application.

Several of the above processes and subroutines may occur simultaneously.For example, while a butt splice 40 is being made (FIG. 16 ) and a gumstrip 42 is being applied over a previously made butt splice (FIG. 24 ),another gum strip 42 may be cut to size and moved into the gum stripapplier 44 (FIGS. 22 & 23 ). FIG. 25 is a state diagram of a program forthe controller 98 permitting several operations or subroutines tooperate simultaneously.

If, at 580, there is no gum strip 42 on the gum strip conveyor 142, thecontroller 98 may execute, at 581, the subroutine of FIG. 22 to cut agum strip to length. If a gum strip 42 is on the conveyor 142, thecontroller 98 may determine, at 582, whether the vacuum head 182 isempty; and if so, may execute, at 583, the subroutine of FIG. 23 to pickup the gum strip from the conveyor 142. If the vacuum head 182 isholding a gum strip 42, the controller 98, at 584, may determine whethera butt splice 40 is in position and ready to be made. If so, thecontroller 98, at 585, 586, may proceed to make a butt splice 40 byexecuting the butt splice subroutine of FIG. 16 and simultaneously applya gum strip 42 to a previously made butt splice 40 by executing thesubroutine of FIG. 24 . If the controller 98, at any time, detects, at584, that a butt splice 40 is not in position and ready to be made, thecontroller may bring a new cut piece 32 into the butt splicer 36 byexecuting the position preparation ply subroutine of FIG. 11 .

The location of the gum strip applier 44 may be adjusted with respect tothe butt splicer 36 to accommodate different widths of calenderedmaterial supplied to the infeed conveyor 34. Referring to FIG. 19 , eachside of the gum strip applier frame 127 may have grooved rollers 136mounted on opposite sides of a linear guide 137 attached to the base128. As shown in FIG. 18 , a ball screw and nut assembly 138 may bemounted to the base 128. A handwheel 139 may be operatively connected tothe ball screw nut and may be rotatably mounted to the frame 127.Rotation of the handwheel 139 may rotate the ball screw nut to move theframe 127 and the components supported thereby with respect to the base128 and the butt splicer 36. Thus, calendered material of differentwidths may be readily accommodated. When the location of the frame 127and gum strip conveyor 142 is changed, feeding of the gum strip 42 fromthe preparation equipment 48 (FIG. 5 ) may also be adjusted, forexample, by moving the location of the preparation equipment.

When making large (e.g., larger than 30″) pneumatic tires, as describedabove, calendered wire treatments may be stitched together to make acarcass band large enough to encompass the tire building drum. Largepneumatic tires (57″ and 63″ rim diameters) may have five or six sheetsof calendered material stitched together. For example, a pneumatic tirewith five sheets may have four prep splices and one builders splice. Theprep splices may be uniform and consistent these splices are cut,aligned, and “zipper” stitched by precision machinery. The builderssplice may be inconsistent since this splice is cut, aligned, and zipperstitched by hand. In cured pneumatic tires, a perfect splice may achieveuniform spacing close to what the “as calendered” one-piece materialachieves. This is called 100% spacing. If zipper stitched materialspreads more than the distance between adjacent cords, the splice may berated on a percentage stretch level. Splices that approach 100% spacingproduce increased durability of the tire casing.

As described above, conventional methods rely on human tire builders tohand cut ply treatment between the steel cords, splitting the rubberbetween those cords that may be only 0.040″ of an inch thick. This mayresult in inconsistent rubber amounts being left that are stitchedtogether and splices that vary in spacing a large amount. A splice inaccordance with the present invention may allow human tire builders touse wire cords in the ply treatment as a guide for cutting each side tobe joined flush against the wire cord thereby leaving no material withinthe splice to be stitched. A 0.020″ wrap around gum strip may be appliedaround the guide cord to both sides of the splice resulting in uniformgauge between the guide cords to be zipper stitched. Splice quality andconsistency may be greatly improved.

As shown in FIGS. 1-3 , both edges 221, 222 of two plies 211, 212 to bejoined may be shaved such that the nearest wire cords 233 are exposed atthe edges (FIG. 1 ). These plies 211, 212 may have a substantiallyuniform spacing W₁ between the wire cords. Only one edge 221 may then bewrapped by a gum strip 244 having a nominal thickness W_(S) equal to thespacing W₁ between the wire cords of the plies 211, 212 (FIG. 2 ). Thegum strip 244 may be a material at least 20% softer than the rubber, orsubstrate, material of the plies 211, 212. The gum strip 244 may wraparound the edge 221 such that the gum strip forms a U-shaped structurein section that allows the gum strip to extend from a first side of theply 211 over the edge 221 of that ply to a second side of that ply 211(FIG. 2 ). The edges 221 may be placed in abutting relationship with theother ply 212 with the gum strip 244 therebetween (FIG. 3 ). The plies211, 212 may thereby be stitched together while preserving ormaintaining the uniform spacing W₁ between the wire cords. Thesestitches 255 may each extend from a first planar side of the first ply211 to a first planar side of the second ply 212 and from the gum strip244 to the first planar side of the second ply (FIG. 3 ).

While the present invention has been illustrated by a description ofvarious examples and while these examples have been described inconsiderable detail, it is not the intention of Applicant to restrict orin any way limit the scope of the appended claims to such detail.Additional advantages and modifications will readily appear to thoseskilled in the art. For example, in a described example, the engagementactuators 85, 90 and clamping actuator 82 are described as pneumaticcylinders; as will be appreciated, in alternative example, thoseactuators may be hydraulic actuators or electromechanical drive systemsor other suitable drive systems.

Therefore, the present invention, in its broadest aspects, is notlimited to the specific details shown and described. Consequently,departures may be made from the details described herein withoutdeparting from the spirit and scope of the claims which follow.

What is claimed:
 1. A method for forming a butt joint between ends offirst and second plies and splicing the first and second plies together,the method comprising the steps of: positioning a first splice edge ofthe first ply at a first location; positioning a second splice edge ofthe second ply at a second location; wrapping a first gum strip aroundthe first splice edge such that the first gum strip forms a U-shapedstructure in section that allows the first gum strip to extend from afirst planar side of the first ply over the first splice edge to asecond opposite planar side of the first ply; not wrapping a second gumstrip around the second splice edge; placing the first splice edge inabutting relationship to the second splice edge; stitching the firstsplice edge to the second splice edge such that stitches each extendfrom the first planar side of the first ply, through the first gumstrip, to a first planar side of the second ply; and curing the firstsplice edge to the second splice edge.
 2. The method as set forth inclaim 1 wherein the first and second plies both have parallel wire cordsspaced a predetermined distance apart.
 3. The method as set forth inclaim 2 wherein the first gum strip has a thickness equal to thepredetermined distance of the first and second plies.
 4. The method asset forth in claim 1 wherein the first gum strip is constructed of amaterial at least 20% softer than a substrate material of the first andsecond plies.
 5. A method of forming a continuous material ply of thetype used to make vehicle tires, the continuous material ply being madeby joining multiple plies, the method comprising the steps of:positioning a first splice edge of a first ply at a first location;positioning a second splice edge of a second ply at a second location;wrapping a first gum strip around the first splice edge such that thefirst gum strip forms a U-shaped structure in section that allows thefirst gum strip to extend from a first planar side of the first ply overthe first splice edge to a second opposite planar side of the first ply;not wrapping a second gum strip around the second splice edge; placingthe first splice edge in abutting relationship to the second splice edgeat a third location; stitching the first splice edge to the secondsplice edge such that stitches each extend from the first planar side ofthe first ply, through the first gum strip, to a first planar side ofthe second ply; and curing the first splice edge to the second spliceedge.
 6. The method as set forth in claim 5 further comprising:providing pairs of upper racks having teeth and extending end-to-endhaving first upper racks movable with respect to second upper racks;providing pairs of lower racks having teeth and extending end-to-endadjacent the pairs of upper racks, the pairs of lower racks having firstlower racks movable with respect to second lower racks; positioning thefirst splice edge of the first ply over teeth of the first lower racks;positioning the second splice edge of the second ply over teeth of thesecond lower racks; clamping the first and second plies between thepairs of upper racks and the pairs of lower racks; simultaneouslyengaging teeth of all first upper racks with teeth of all second upperracks; and teeth of all first lower racks with teeth of all second lowerracks to firmly press the first splice edge of the first ply against thesecond splice edge of the second ply to splice the first and secondplies together.
 7. The method as set forth in claim 5 wherein the firstgum strip is constructed of a material at least 20% softer than asubstrate material of the first and second plies.
 8. A tire comprising acontinuous material ply, the continuous material ply being made byjoining multiple plies, the tire including: a first splice edge of afirst ply at a first location; a second splice edge of a second ply at asecond location, the second splice edge being left bare; a gum stripwrapped around the first splice edge such that the gum strip forms aU-shaped structure in section that allows the gum strip to extend from afirst planar side of the first ply over the first splice edge to asecond opposite planar side of the first ply, the gum strip beingconstructed of a material at least 20% softer than a substrate materialof the first and second plies, both the first ply and the second plyhaving predetermined uniform spacing between wire cords in the first plyand the second ply, the predetermined uniform spacing being equal to anominal thickness of the gum strip; the first splice edge being placedin abutting relationship to the second splice edge at a third location;the first splice edge being stitched to the second splice edge such thatstitches each extend from the first planar side of the first ply,through the gum strip, to a first planar side of the second ply; and thefirst splice edge being cured to the second splice edge.